a. Field of the Invention
This invention relates to a print control method and system for use with a printer having a reduction/magnification function therein. More particularly, this invention relates to a print control method and system especially suited for control of print data having various printing formats such as printing magnifications or printing scale sizes.
b. Background Art
When jobs executed or processed by a data executing or processing unit are required to be printed out, print data of the jobs are stored sequentially in a storage, so-called spool (simultaneous peripheral operations online) file. The stored data are then taken out sequentially and sent to a printer to be printed out thereby. FIG. 4 illustrates a general configuration of a printing system.
The printing system shown in FIG. 4 comprises a job executing section 402, a spool file 403 used as a storage for storing print data obtained as results of job execution by the section 402, a printer 406 for printing out the print data on paper, a printer control unit 405 for controlling the printer, and an output control section 404 for outputting the print data stored in the spool file 403 to the printer control unit 405.
The job executing section 402 and the output control section 404 may be provided in the form of hardwares specifically dedicated thereto, respectively, or they may be functions implemented in combination by a central processing unit (CPU) 401 and a software. The spool file 403 comprises a storage in the form of a hardware and it is under control of CPU 401.
In the printing system as illustrated in FIG. 4, printing of data is controlled as follows:
A job applied to CPU 401 is executed by the job executing section 402 and the execution results are stored sequentially in the spool file 403. Upon receipt of an output demand, CPU 401 actuates the output control section 404. The output control section 404 sequentially outputs and sends the execution results, namely, print data and output format, which are stored in the spool file 403, to the printer control unit 405. The printer control unit 405 edits the print data according to the output format and converts the same into dot data. The print data is then sent to the printer 406. The printer 406 outputs the data in the form of print on paper.
Prior arts related to the printing system of the type as described above include, for example, a job execution result output control system as disclosed in Japanese Publication of Unexamined Pat. Application (KOKAI) No. 57-21253 which is capable of inhibiting unnecessary job print-output in the data processing system for print-outputting the program execution results.
Japanese Publication of Unexamined Pat. Application No. 58-115536 discloses an automatic printing system suitable for data printing which involves repetitious routine operation as can be seen in printing out of a spool magnetic tape. In this system, once job is initiated, the printing can be carried out continuously only by replacing magnetic tapes. Thus, initiation operation for a new job which would otherwise be needed upon every replacement of magnetic tapes is not required any more.
Another Japanese Publication of Unexamined Pat. Application No. 62-60026 discloses an arrangement for a relatively small-scaled computer system in which print data transmitted from a plurality of processing units which operate independently of each other can be outputted pigeonholedly by processing units through a single printer.
In this connection, it is to be noted that some printer such as a laser beam printer has a function of effecting reduction and/or magnification printing. This type of printer may be applied to a printing system as shown in FIG. 4. This is illustrated in FIG. 5.
The printer as illustrated in FIG. 5 comprises a laser beam generating unit 502, a modulator 504 for modulating a laser beam 503 emitted from the laser beam generating unit 502 by a modulating signal 501 from the printer control unit 405, a reflection mirror 505 for reflecting the modulated laser beam from the modulator 504, a photoconductive drum 508 for forming a latent electrostatic image by the modulated laser beam irradiated thereon, a polygon mirror 506 for reflecting the reflected laser beam 503 so as to scan the surface of the photoconductive drum 508, and an FO lens 507.
In the printing system shown in FIG. 5, the photoconductive drum 508 and the polygon mirror 506 are rotated with a given period to effect printing. The dot data transmitted from the printer control unit 405 is applied to the modulator 504 as a modulating signal to modulate a laser beam 503 emitted from the laser beam generating unit 502. The modulated laser beam 503 irradiates the photoconductive drum 508 through the reflection mirror 505, the polygon mirror 506 and the FO lens 507. As a result of this, a latent electrostatic image corresponding to the irradiated beam patterns is formed on the photoconductive drum 508. The electrostatic image is developed by a toner. The toner image is transferred to paper and fused by heat to make it permanent. Thus, printing is attained.
In the printing system as described above, magnification or reduction may be changed by changing the rotation periods of the photoconductive drum 508 and the polygon mirror 506. For example, the rotation period of the photoconductive drum 508 is extended or the rotational speed is reduced, and the rotation period of the polygon mirror 506 is shortened or the rotational speed thereof is increased to reduce the size of the latent image formed on the photoconductive drum 508. The image is developed and transferred onto paper to attain printing in reduced scale.
In the printing system as illustrated in FIG. 4, the print data stored in the spool file 403 as the result of the job execution are selected to be printed on the first-stored first-served basis. Even though the printing conditions, especially, printing magnifications of the print data are different from each other, the print data are transmitted to the printer according to the order in which the data have been stored. Consequently, the printing magnifications of the respective data are read to be set in the printer in the order and the data are printed in the order, too. Therefore, if the printing magnifications of the data are different from each other, the printing magnification to be set in the printer must be changed upon every change of the print data.
However, when the photoconductive drum 508 and the polygon mirror 506 are instructed to change their rotation periods for changing the printing magnification, they can not be controlled to the desired rotational periods immediately. It requires a certain time to put them into stable rotation. Therefore, if the printing magnifications of the print data are different, the setting of the printing magnification must be changed upon every change of the print data. It requires an adjusting time whenever the printing magnification is changed. Thus, the entire printing requires longer time.
It is now assumed that three jobs of different printing magnifications, for example, a first job of output format B, a second job of output format A and a third job of output format B are stored in the spool file 403, and that the output format A corresponds to print magnification of 100% (original size) and the output format B to printing magnification of 80% (reduction). It is further assumed that it takes, for example, about 3 minutes to change the printing modes from B to A or vice versa. In this case, if the printing now completed is not in mode A, it takes about 12 minutes in total for changing the modes only, if the first job is printed in mode B, the second job in mode A, the third job in mode B and a further job is to be set in another mode. Thus, when it is required to print data of a number of jobs, it requires a considerable time to complete the printing thereof.
As can be understood from the description given above, every change of the printing magnifications requires an adjusting time, which is necessitated in the printing of a number of jobs having different printing magnifications in the printing system having a function of setting a printing magnification therein. It, therefore, requires a considerably long time to complete entire printing of the data.
Of course, a light emitting diode array may be used as a light source for a printer. In this case, however, the rotational period of the photoconductive drum must also be changed. This again will cause similar problems to those as described above.